Phaeochromocytoma

Question 1

What is a phaeochromocytoma?

Answer 1

Adrenal medullary tumour, secretes catecholamines (Noradrenaline and adrenaline)

Question 2

What are the causes?

Answer 2

Usually inherited, associated with
MEN 2a+2b (multiple endocrine neoplasia)
Neurofibromatosis I (tumours deposited along nerve - myelin sheath)

Question 3

Sx ?

Answer 3

Hypertension
Pallor
Very sweaty
tachycardia

Question 4

Dx?

Answer 4

Plasma metanephrines + normetanephrines (DIAGNOSTIC)
+ urinary catecholamines + CT image tumour)

Question 5

Why are plasma metanephrines detected instead of adrenaline?

Answer 5

More sensitive readings than NAd/Adr
Longer 1/2 life

Question 6

Tx?

Answer 6

Alpha blocker FIRST (eg. phenoxybenzamine)
then Beta blocker (eg, atenolol)

Surgery if possible to excise tumour

Question 7

Why is an alpha blocker used first?

Answer 7

This prevents reactive vasoconstriction

Question 8

Complication?

Answer 8

HTN crisis (180/120)

Question 9

What is the cause of HTN crisis?
What would you give?

Answer 9

Causes = X ray contrast, TCA, opiates
Give phentolamine (alpha blocker)